Synthesis, characterization, and properties of silicon (IV) compounds containing <i>N,N'</i>-symmetrically alkyl substituted 1,3-diketimine ligands and their potential as CVD precursor material

<p></p> <p>A family of silicon (IV) compounds containing <i>N,N'</i>-symmetrically alkyl substituted 1,3-diketimine ligands as chemical vapor deposition (CVD) precursors for silicon-based films has been reported and characterized by ¹H, ¹³C, and ²⁹Si NMR, EI-MS and elemental analysis where necessary. The compounds were synthesized by reaction of corresponding lithium salt of the diketimine ligands and SiMe₃Cl according to a general procedure. Theoretical simulation was performed in order to understand their structures. Thermal stability, transport behavior and vapor pressures were evaluated by simultaneous thermal analyses (STA). Chemical vapor deposition was accomplished in a hot wall CVD reactor system to further demonstrate the ability of these compounds as CVD precursors. Characterization (SEM and XPS) of the as-grown films proved that the family indeed possesses the potential to fabricate silicon-based films with compact and uniform structure.</p

Synthesis, characterization, and thermal properties of silicon(IV) compounds containing amidinate ligands as CVD precursors

<p>The title compounds of the type R-C(=N^<i>i</i>Pr) (-N′ ^<i>i</i>PrSiMe₃) (with R = Me or ^<i>n</i>Bu) as potential chemical vapor deposition (CVD) precursors have been synthesized and characterized by ¹H, ¹³C, and ²⁹Si NMR spectroscopy as well as by EI-MS and elemental analysis where necessary. Thermal properties, including stability, volatility, transport behavior, and vapor pressure, were evaluated by thermogravimetric analysis to confirm that they are suitable for the CVD procedure. Deposition was accomplished in a hot wall CVD reactor system, which qualitatively verified the ability of these compounds as CVD precursors.</p

Synthesis of two aminosilanes as CVD precursors of SiC_xN_y films: Tuning film composition by Molecular Structures

<p></p> <p>Two aminosilanes derived from hexamethyldisilazane as chemical vapor deposition (CVD) precursors for SiC_xN_y and relevant films have been reported and characterized by ¹H, ¹³C, and ²⁹Si NMR as well as by EI-MS and elemental analysis, where necessary. Thermal stability, transport behavior and vapor pressures were evaluated by simultaneous thermal analyses (STA). Chemical vapor deposition was accomplished in a hot wall CVD reactor system to further demonstrate the ability of these compounds as CVD precursors. Most importantly, characterization (XPS) of the as-grown films proved that the composition of the films can be controlled by the molecular structure of the precursors. The result suggests future strategy for the design of CVD precursors for SiC_xN_y and related films.</p

Scalable Conversion of CO₂ to N‑Doped Carbon Foam for Efficient Oxygen Reduction Reaction and Lithium Storage

With regard to CO₂ usage for the sustainable production of value-added chemicals, this work provides a fast pyrolysis process for the first time that can be scaled up in directly capturing CO₂ to produce N-doped carbon foam (NCF) as a functional nanomaterial. Flammable alkaline solutions of hydrazine hydrate serves as CO₂ adsorbent, fuel as well as nitrogen source for the NCFs, and magnesium powders are involved into the reaction to provide complex metal ion and also energy for the self-propagating high-temperature combustion pyrolysis. The prepared NCFs exhibit efficient electrochemistry performance toward lithium-ion battery and oxygen reduction reaction benefiting from the well-formed foam structure with hierarchical pores, in situ nitrogen doping and high specific surface area. More importantly, this approach introduce a general solution system that can further integrate various additives dissolved homogeneously, thus greatly increasing process controllability and product selectivity for the thermochemical conversion of CO₂